The long-term goal of this research is to find a more effective medical and pharmacological management of ureteral calculus disease. It is hypothesized that calculi pass down the ureter best when the ureter is inactive and the pressure proximal to the calculus is low. In this proposal a chronic animal model will be used. A surrogate calculus will be introduced in a retrograde direction into the ureter via a bladder explant. The size will be chosen that will traverse the ureter in approximately 1-3 weeks. Not only will the effects of variations in urine flow and smooth muscle relaxants be tested, but also the effects of edema, anti-inflammatory agents and activity. Female dogs have been chosen for the experimental animal. Ureteral activity will be monitored by a pair of implanted optical sensors and renal pelvic pressure via a totally implanted nephrostomy tube. Access for pressure management will be via a needle puncture of the subcutaneous heparin lock, which is attached to the nephrostomy tube. Over the course of 1-3 weeks the effects of activity, fluid intake and anti-inflammatory drugs will be studied. In the more acute experiments, when the caluclus becomes arrested in the ureter, the effects of intravenously administered smooth muscle relaxants and diuretics will be investigated.